Shrapnel plug



April 21, 1925.

M. E. DUNLAP SHRAPNEL PLUG Filed Nov. 5, 1918v Z Z w M, w v

i ii) Patented Apr. 21, 1592!.

isir-Mrs isaiaoi Pfn reNT lofFrroE.

' `ng' DNLAP; or *Mnijrson 'wisoonslrhr Assreivon 'To 'UNITED srn'rns :or AMERIGA.

SHRAPNEL PLUG.

anpiication fiidiaovembers, 1918. seriarnojeereos.

a citizen oflthe United States, i'esiding at ,Madisominthe countyof Dane and State of 't'hus drawn into the opening until the head' Wisconsin, have invented certain'new and 'useful jlmprovements infshrapnel Plugs,` of wl'xich the following is a specification.

My invention relates to plugs for'shrapnel shells and the object of my invention is to provide aplug satisffactory for this use constructed of wood. The useof w'ood for such a--plug isV extrvelnely desirable in that wood is inexpensive and also is easily worked. -leretofo`re, however, so far as I know, no woodenplug has been produced which was so t constructed that 'it would' not bi-nd in the` opening upon being en'posed to moisture. Such binding will'hainper the reinoval ofl the plugs and in many cases V'the plugs 'swell to such a degree as to render impossible the removal thereof without injuryto the shell. Vhfyfplug isdesigned to completely close the opening :in the shell and vet is so eo'nstructed that exposurelto inoisture and he swelling consequent thereto will cause no appreciable binding` of the plug in the opening.

.l have designed two types of plug which fuliill the objects of my invention. I have shown one type in Figures 1 and 2, Figure 1 being a top plan view of niy plug and Figure 2 a central vertical section. The other form of plug which I have designed is illustrated in Figures 3, 4 and 5, wherein Figure 3 represents a top plan view of the }'lug Figure L1 a central vertical section along the line l--lz of Figure 3, and Figure 5 a section at right angles to the section of vl `igure 4 and along the line 5-5 of Figure 3.

l'leferring to Figures 1 and 2 for a description of the first form of plug7 1 represents a o vlindrical annular body provided on its exterior` surface with threads 2. This body 1 is shouldered at 8 to merge into a ueck part 1 which is hollowed at its lower side as a con'tinuation of the opening in the body 1 but is closed at its upper end. This closurc at the upper end nierges into a head 5 provided with an over-hanging portion 6 of greater diinension than the over all din'iension of the threads 2. This head is also provided with a serew slot 7 to facilitate insertion and removal of the plug.

lt will be apparent from the consideration i I w H :of the above described plug that the open- Be ity known that l MA'r'ri-Inw E. DUNLAP,

ingfwhich4 is also threade'd, is 'engaged by the threads on the annulus 1 and the plug` :3 "makes tight contact with the edges thereof. ln` the event of niolsture entering the plug i the various parts' of the plug will swell. An

inspeotion of the drawing will show, how- 'cveiy' that swelling of t'lie3head part 5 'willv inerely cause this part to eXtend itself over the surface of the shell. Expansion of the neclr piece 4; will be ineffective to cause bi'nding betweenthis part and the shell 'opening due to the s'inaller dianieter of the iieck `iresul'ting,v froni the inset at shoulder lilxpansion of the annulus 1 would cause vbinding but this adnnulu's 'is made so thin that the expausionis not only materially reduced but also the compression which niay be exei'ted to cause binding is greatly reduced. Duetothis construction there will be nol appreciablebinding between the annulus 1 and the shell opening. t will be al'rparent frorn the above that niy plug` will;U

not bind appreeiably lupon exposure to moisture.

Referring to Figures 8, Li, and 5, for a description of the second forin of plug, 11 represents a cylindrical body provided with a recess 12 of rectangular cross-section extending diametrically therethrough. EX- tending through this recess 12 is a rod 13 provided on its ends with screw threads 14 and so arranged that its grain is parallel to the axis of the opening` 12. At. its upper end the body 11 expands at Shoulders 15 to forin a head 1G of greater' diameter than threads 14. This head 16 is also provided with a slot 17 to facilitate the insertion and withdrawal of the plug.

A eonsideration of the above description will show that this' plug is secured in the opening by means of the rod 13 through the engagenient of the threads 14 thereon with corresponding threads in the shell opening. The plug` is screwed into the opening until the head 16 seats firnily on the surface of the shell and thus closes the opening. Should the plug` now be moistened.` inspection of the drawing will show that the resulting swelling of head 1.6 will Inerely cause it to extend over the surface of the shell and the resultant expansion of body 11 will be inetfective to cause binding because of the reduced diaineter of the body which pre- Yents it from coming in contact with the It Will be apparent that I may use means to secure the plug in the shell other than a continuous screw thread, such for example as a segmental thread or a bayonet slot construction. IVhatever method of securing is employed my construction will operate with equal efiiciency to properly close the opening without causing binding. I also realize that other' materials than wood may be used for part or all of either plug. It Will be apparent that where such material possesses the same properties of expansion by acquisition of moisture, my invention will be applicable throughout to this material. IV here such material is substituted for apart of the plug other than that which functions to secure the plug' to the Shell, it will be appa-rent that such substitution does not in any way differentiate from the essential elements of my plug. It will also be apparent that in the construction shown by Figures 1 and 2 the opening is closed by both the body of the plug and the head thereof.

I realize that this duplication of closures may bc found unnecessany and one dis-v pensed with. In the construction shown in Figures 8, 4, and 5, the body does not completely close the opening, yet for many purposes it closes it to a sufiicient degree. Aceordingly this construction also provides a duplication of closures and again I realize that one may well be cmitted. Further, in the construction shown in Figures 3, 4, and 5 I realize that a plurality of rods may be substituted for the one rod. Also these changes and modifications I consider to be within the scope of my invention. I also realize that my plug is not limited to use in shells and I do not consider my invention in any way limited to that use. I also consider as Within the scope of my invention all modifications included within the scope of the appended claim.

A cylindrical plug for shrapnel shells comprising a body of Wood having one portion of an external diameter. greater than that of the hole to bev plugged, a threaded portion for retaining said plug in said hole, said body having a cavity formed in one end extending into said body beyond said threaded portion, and a portion of lesser diameter than said hole and said screw threaded portion, arranged between Said threaded portion and said portion of greater diameter than said hole. a

In testimony whereof I afiix my signature.

MATTHEV E. DUNLAP. 

